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A034293 Numbers n such that 2^n does not contain the digit 2 (probably finite). 6
0, 2, 3, 4, 6, 12, 14, 16, 20, 22, 23, 26, 34, 35, 36, 39, 42, 46, 54, 64, 74, 83, 168 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Is 168 the last term?

First row of A136291. - R. J. Mathar Apr 29 2008

LINKS

Table of n, a(n) for n=1..23.

MAPLE

isA034293 := proc(n) RETURN(not 2 in convert(2^n, base, 10)) ; end: for n from 0 to 100000 do if isA034293(n) then print(n) ; fi ; od: # R. J. Mathar, Oct 04 2007

MATHEMATICA

Join[{0}, Select[ Range@10000, FreeQ[ IntegerDigits[2^# ], 2] &] (* Shyam Sunder Gupta, Sep 01 2007 *)(* adapted by Vincenzo Librandi, May 07 2015 *)

Select[Range[0, 10^4], DigitCount[2^#][[2]] == 0 &] (* Michael De Vlieger, Apr 29 2016 *)

PROG

(MAGMA) [n: n in [0..1000] | not 2 in Intseq(2^n) ]; // Vincenzo Librandi, May 07 2015

(PARI) is(n)=setsearch(Set(digits(2^n)), 2)==0 \\ Charles R Greathouse IV, May 10 2016

CROSSREFS

Cf. similar sequences listed in A035064.

Sequence in context: A018309 A245481 A039038 * A136291 A128393 A057919

Adjacent sequences:  A034290 A034291 A034292 * A034294 A034295 A034296

KEYWORD

base,nonn

AUTHOR

Erich Friedman

EXTENSIONS

Edited by N. J. A. Sloane, Oct 03 2007

Removed keyword "fini" since it is only a conjecture that this sequence contains only finitely many terms. - Altug Alkan, May 07 2016

STATUS

approved

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Last modified June 29 18:25 EDT 2022. Contains 354913 sequences. (Running on oeis4.)